If you need the lowercase or uppercase version of an operating system identifier, such as a file name, named pipe, or registry key, use the ToLowerInvariant or ToUpperInvariant methods.

• 如果您需要操作系统标识符(如文件名、命名管道或注册表项)的小写或大写版本,请使用ToLowerInvariant或ToUpperInvariant方法。